Stressed skin airfoil joint



Aug. 14, 1945. M WATTER i 2,382,358

` sTREssED SKIN AIRFoIL JOINT Filed Feb. 3, 1944 2 Sheets-Sheet l' IlllINVENTOR Michael Wct ATTORNEY -2 Sheets-Sheet 2 M. WATTER STRESSED SKINAIRFOIL JOINT Filed Feb. s, 1944 Aug. 14, 1945'.

INVENTOR Michael Waiter.

Gru-uy ATTORMEY Patented Aug. 14, 1945 Edward G. Budd ManufacturingCompany, Philadelphia, Pa., a corporation of Penns'yivania ApplicationFebruary, 1944, serial No. 520,862

7 crains. y(ci. 24e-131)' This invention relates to stressed skinairfoils and has for an object the. provision of improved means forjoining together two adjacent reinforced skin sections.

The .structure of the present application is animprovement for certainuses upon the structure disclosed in the copending application ofMichael' Watter, 'Serial No. 385,235, filed March 26, 1941.

One of the particular objects of the invention is to providejoining'means for the ends of reinforced skin coverings which haveoverhanging Stringer elements.

Another object lis to provide joining meanswhich is associated through arib web with the' ends of similar reinforced skin coverings on thelOpposite sides of the rib.

n Another object is to provide joining means which can be introducedabout the overhanging stringers without cutting, flattening, orotherwise deforming-the stringer members.

'I'he above and other objects of the invention will be evident from thefollowing description ,of

an illustrative embodiment, reference being made to the accompanyingdrawings, wherein:

Fig. 1 is a perspective sectional view of a blanket rib joint;

Fig. 2 is a plan section; Fig. 3 is a section taken on the line 3-3 of2; and

Fig. 4 is a perspective of a joint fitting. The skin blankets i whichare A'to be joined Fig- Y 2 2 parallel with the skin sheet, and an endflange each includes a skin Ii and a plurality of stiifening strlngersi2 attached thereto, as by welding. The stringers are of theflanged-Y-bulb type whereinthe anges |2a are secured to the skin sheet,as by welding, and the bulb |2b constitutes an overhang beyond the webor stem i2c. Where a joint is to be made the skin sheets il extendbeyond the ends of the stringers unless it is desired to join the 'endsof the adjacent sheets by a splice or cover sheet. The skin sheet jointmay be reinforced interiorly by a finger plate I4 comprising a thickbody strip i5 and fingers i6 which extend out into the spaces within theStringer,

flanges i2a.. In the nal assembly the fingers i6 are welded to the skinand flanges.L

The joint may be made at any point along the skin blanket butvpreferably is made above and secured to a rib. Such arib is shown hereinand comprises a web i-and one or more chords or cap strips I9 weldedthereto. 'Ihe linger plate Ml rests on the tops of the cap strips.

The stringers are connected by joint fittings 20 of corneriron shapehaving a body side portion 2| shaped to fit the side of a stringer, aside flange 23 parallel with the rib web. Two fitting members 20, ormore properly the two parts of a stringer fitting, are secured to theend of a Stringer by bolts 2l passing through the web I 2c of thestringer and bolts 25 passing through the Stringer bulb 1 walls.

Nuts and washers may be preliminarily inserted from the end of the bulband secured inside ready for use. y

The end-flanges 23 of the fittings abut the rib here engaging theflanges of the cap strips l 9, and are secured 'together against theside of the rib by bolts 26. A I

The blanket joint as thus made is very strong and rigid; the stringersrequire no trimming or flattening; and the fittings can be insertedafter the blankets and rib have been brought into .final position.

While one embodiment of the invention has been described for purposes ofillustration, it is to be understood that there may be variousembodiments within thelimits of the prior art and the scope of thesubjoined claims.

What is claimed is:

1. In an airfoil structure in combination, a skin blanket including askin sheet and stringers secured thereto, said stringers includinglaterally overhanging elements at a distance from the skin, and meansfor connecting the stringers to anv adjacent part including fittingsconforming to the shape of the side of the stringers, said fittingshaving endanges, means connecting the fittings on opposite sides`of aStringer together through the Stringer, and means connecting theiittings through their end flanges to the adjacent part. l

2. In an aix-foil structure-in combination, a skin blanket including askin sheet and stringers secured thereto, the stringers being offlanged- Y-bulb shape in section with the flanges secured to the skinsheet,'and' means for connecting the stringers to an adjacent partincluding fittings conforming'to the shape of the sides o the stringere,said fittings having end flanges, means connecting the fittings onopposite sides of a stringer'together through the web and bulb of thestringer, and meansconnecting the fittings through their end flangestothe adjacent part.

3. In an airfoil structure in combination, adjacent skin blankets eachincluding askinsheet and stringers secured thereto, a rib web betweenadjacent skin blankets, the strlngers beingdis- I posed in end-adjacentrelation in pairs at said rib web, iittings on each side of a Stringersecured together through the `stringer, said fittings f end iianges. and:new Securing the end web.

4. In an airfoil structure in combination, adjacent skin blankets eachincluding a skin sheet and stringers secured thereto. the stringershaving laterally overhanging portions spaced from the skin sheet, a ribweb plate between adjacent skin blankets, the stringers being disposedin end adjacent relation in pairs at said rib web plate, fittings oneach side of a Stringer secured together through the stringer,the'iittings having end anges abutting the rib web plate, and meanssecuring the end anges of the Stringer ttings on the same side of theend-adjacent stringers together through the rib web plate.

5. In an airioil structure in combination, adjacent skin blankets havingaligned stringers secured to skin sheets, a rib web plate between theends of the stringers, a joint plate above the web between the Stringerends and having projections plate secured to the skin sheets, thestringers being of iianged-Y-bulb shape with their flanges secure to theskin sheets, and a comer-shaped fitting on each side of a Stringer endhaving one side conforming to the sides of the Stringer web and bulb,having an end iiange parallel with the rib web plate and a lateralflange parallel with and spaced from the skin sheet, bolts passingthrough thesides of both ttings of a Stringer and the Stringer web andbolts passing through the sides of the ttings and the sides oi the bulboverlying and secured to the Stringer flanges, and means connecting theouter portions of the stringers above their flanges together.

'7. In an airioil structure in combination, a

skin blanket including a skin sheet and stringers secured thereto, saidstringers including a flange secured to the skin sheet, a web portionextending away from the skin sheet, and a laterally .overhanging portionat a distance from the skin sheet. and means for connecting thestringers to an adjacent part including ttings on opposite sides of thestringers conforming to the shape of the side of the web and overhanginPOrtion of' the Stringer, said` fittings having end ilanges, meansconnecting the ttings on opposite sides of a Stringer together throughthe web and through the overhanging portion of the Stringer, and meansconnecting the llttings through their end anges to the adjacent part.

. MCHAEL WATTER.

